In order to measure a target component in blood, methods of detecting an electrochemical signal or an optical signal with the use of a biosensor have been used widely. A signal value, which indicates the magnitude or intensity of the signal, corresponds to the amount of the target component. Thus, by measuring the signal value, the amount of the target component in blood can be measured.
In such measurement, the influence of the hematocrit value of blood has been regarded as a problem. In general, the normal value of the hematocrit value of blood is set to 30% to 55%. However, the hematocrit value of anemic blood may be lower than the normal value, while the hematocrit value of polysynthetic blood may be higher than the normal value. As such, the Ht value of blood varies from one person to another. Thus, when the measurement of a target component is performed on a blood specimen whose Ht value is unknown, there arises a problem that, owing to the influence of the Ht value, the amount of the target component cannot be determined accurately.